Joint prosthesis is an artificial implant. Some human joint problems, such as proliferation of bone spurs and articular surface degeneration, caused by unexpected accidents, sport injuries, repetitive pressures, or pathological changes may need to replace the human joint with the joint prosthesis by means of surgical operations. There are various joint prostheses, such as artificial knee, artificial hip, artificial shoulder, and artificial wrist.
The joint prosthesis generally includes a connecting device which is implanted into a medullary cavity of a bone and is for receiving a bone structure near the bone. However, the bone and the muscle are structurally different for every individual person, so the connecting device of the joint prosthesis should be designed for individual patients regarding musculoskeletal mechanics so as to be suitable for patients and to help patients recover.